“Visioning means imagining. At first generally, and then, with increasing specificity, what you really want. That is what you really want. Not what someone else has taught you to want and not what you have learned to settle for. Visioning means taking off all of the constraints of assumed feasibility, of disbelief and past disappointments and letting your mind dwell upon its most noble, treasured, uplifting dreams. Some people, especially young people, engage in visioning with enthusiasm and ease. Some people find the exercise of visioning painful because a glowing picture of what could be makes what is all the more intolerable. Some people would never admit to their visions for fear of being thought impractical or unrealistic. They would find this paragraph uncomfortable to read, if they were willing to read it at all. And some people have been so crushed by their experience of the world that they can only stand to explain why any vision is impossible. That’s fine, they are needed too. Vision does need to be balanced with skepticism. We should say immediately, for the sake of the skeptics, that we do not believe that it is possible for the world to envision its way to a sustainable future. Vision without action is useless, but action without vision does not know where to go or how to go there. Vision is absolutely necessary to guide and motivate action. More than that, vision when widely shared and firmly kept in sight brings into being new systems. We mean that literally. Within the physical limits of space, time, material and energy, visionary human intentions can bring forth not only new information, new behaviour, new knowledge and new technology, but eventually new social institutions, new physical structures and new powers within human beings. A sustainable world can never come into being if it cannot be envisioned. The vision must be built up from the contribution of many people before it is complete and compelling.”

– Meadows, Donnella H., Dennis L. Meadows and Jørgen Randers

as quoted here